Add zram functionality

log2ram

@@ -50,21 +50,46 @@ wait_for () {
     done
 }
 
+createZramLogDrive () {
+	# Check Zram Class created
+	if [ ! -d '/sys/class/zram-control' ]; then
+		modprobe zram
+		RAM_DEV='0'
+	else
+		RAM_DEV=$(cat /sys/class/zram-control/hot_add)
+	fi
+	echo ${COMP_ALG} > /sys/block/zram${RAM_DEV}/comp_algorithm
+	echo ${LOG_DISK_SIZE} > /sys/block/zram${RAM_DEV}/disksize
+	echo ${SIZE} > /sys/block/zram${RAM_DEV}/mem_limit
+	mke2fs -t ext4 /dev/zram${RAM_DEV}
+}
+
 case "$1" in
   start)
       [ -d $HDD_LOG/ ] || mkdir $HDD_LOG/
       mount --bind $RAM_LOG/ $HDD_LOG/
       mount --make-private $HDD_LOG/
+	if [ "$ZL2R" = true ]; then
+		createZramLogDrive
+	fi
       wait_for $HDD_LOG
-      mount -t tmpfs -o nosuid,noexec,nodev,mode=0755,size="$SIZE" log2ram $RAM_LOG/
+	if [ "$ZL2R" = true ]; then
+		mount -t ext4 -o nosuid,noexec,nodev,user=log2ram /dev/zram${RAM_DEV} ${RAM_LOG}/
+	else
+		mount -t tmpfs -o nosuid,noexec,nodev,mode=0755,size=${SIZE} log2ram $RAM_LOG/
+	fi
       wait_for $RAM_LOG
       syncFromDisk
       ;;
 
   stop)
       syncToDisk
+	#ZRAM_LOG=$(awk '$2 == "/var/log" {print $1}' /proc/mounts)
+	#ZRAM_LOG=$(echo ${ZRAM_LOG} | grep -o -E '[0-9]+')
       umount -l $RAM_LOG/
       umount -l $HDD_LOG/
+	# Unsure as even with Root permision denied
+	#echo ${ZRAM_LOG} > /sys/class/zram-control/hot_remove
       ;;
 
   write)

log2ram.conf

@@ -14,4 +14,20 @@ USE_RSYNC=false
 
 # If there are some errors with available RAM space, a system mail will be send
 # Change it to false and you will have only a log if there is no place on RAM anymore.
-MAIL=true
+MAIL=true
+
+# **************** Zram backing conf  *************************************************
+
+# ZL2R Zram Log 2 Ram enables a zram drive when ZL2R=true ZL2R=false is mem only tmpfs
+ZL2R=false
+# COMP_ALG this is any compression algorithm listed in /proc/crypto
+# lz4 is fastest with lightest load but deflate (zlib) and Zstandard (zstd) give far better compression ratios
+# lzo is very close to lz4 and may with some binaries have better optimisation
+# COMP_ALG=lz4 for speed or Zstd for compression, lzo or zlib if optimisation or availabilty is a problem
+COMP_ALG=lz4
+# LOG_DISK_SIZE is the uncompressed disk size. Note zram uses about 0.1% of the size of the disk when not in use
+# LOG_DISK_SIZE is expected compression ratio of alg chosen multiplied by log SIZE
+# lzo/lz4=2.1:1 compression ratio zlib=2.7:1 zstandard=2.9:1
+# Really a guestimate of a bit bigger than compression ratio whilst minimising 0.1% mem usage of disk size
+LOG_DISK_SIZE=100M
+